Manufacture of metal tubes and tubular articles



Dec. 13,.l938. 5. SMITH 2,140,434

MANUFACTURE OF METAL TUBES AND 'IUBULAR'ARTICLES Filed Feb. 18, 1937UNITED STATES PATENT OFFICE MANUFACTURE OF METAL TUBES AND TUBULARARTICLES Sydney Smith, London, England, assignor to Wellman SeaverRolling Mill Company Limited, London, England, a British companyApplication February 18, 1937, Serial No. 126,498

In Great Britain March 11, 1936 10 Claims.

This invention relates to the manufacture of metal tubes and tubulararticles by a method in which a square or other sectioned billet isheated and then transferred to a container where a punch is forced intoit from one end so that the metal displaced by the punch causes thebillet to fill the container.

In the manufacture of metal tubes and tubular v articles by the pushbench method the punch is forced into the billet to within a shortdistance of the other end and the billet or hollow, now usually termed abottle, is placed on a mandrel and treated in push bench apparatus inwhich it is carried through a series of dies or through passes betweenrolls by which is is drawn out to a tube which is subsequently strippedfrom the mandrel.

In other methods of manufacture of metal tubes and tubular articles, asfor example in which a pilger or automatic mill is employed,

the punch is forced right through the billet so as to produce a tubularhollow open at both ends which is subsequently treated for theproduction of the metal tube or tubular article in the pilger orautomatic mill or other apparatus.

The container usually has a replaceable internal sleeve which isslightly tapered from top to bottom and which is changed according tothe dimensions of the billet to be received. For example,.when a caststeel ingot is cut into lengths andv the separate lengths are employedto produce tubes a different liner may have to be used when dealing withthe length from the small end of the ingot from that required whendealing with the length from the large end of the ingot.

' When using rolled billets they are found often to be over-size, thissometimes causing difliculty in introducing them into the container.

In other words, the billet is seldom of the correct size for thecontainer whereby not only may the liner have to be changed, thusinvolving loss of time in the operation of the plant, but the billet'maybe small and slackin the container f 'so that it may fall to one sidewhereby the piercing is not correctly central and an imperfect bottle isobtained. p

The present invention has for object improvements in the manufacture ofmetal tubes and like tubular articles and in the apparatus employedwhereby cheaper material may be employed, for example, cast billets andmore accurately punched hollows produced with consequent greateraccuracy in the gauge of the finished tube and also a cheaper tube.

The present invention comprises a method of producing a metal tube ortubular article consisting in pressing a heated square or othersectioned billet to reduce its cross-sectional area and form to thatrequired to be received into the container of a punching or piercingapparatus, introducing it into the container of said punching orpiercing apparatus, forcing in a punch from one end, removing thetubular hollow thus produced from the container and treating it in anapparatus to convert it into a tube or tubular article, for example, ina push bench apparatus.

The invention also comprises means for treating the billet consisting ofa press having two parts with depressions in their adjacent faces, apower cylinder formed on or connected to .one part and a piston in saidcylinder connected to the other part so that relative movement of thepiston and cylinder in one direction causes the press parts to .closetogether and in the other direction to open.

One form of press for use in carrying out the present invention will nowbe described by way of example and with reference to the accompanyingdrawing wherein:

Figure l is an elevation partly in section of a press,

Figure 2 a plan, and

Figure 3 shows a modification which may be used in the apparatus ofFigures 1 and 2.

Referring to Figures 1 and 2 the press consists of two parts I, 2positioned face to face with semicircular depressions in their adjacentfaces. The part i is formed'at its end remote from the semicirculardepression with a cylindrical cavity 3 constituting a cylinder in whichis a piston 4. 5 is a gland cover. The ports for the admission ofoperating fluid, such as pressure wa'teror oil, are not shown. f

The piston carries or is attached to acrosshead 6 which is connected tothe part 2 of the press by links I, 8 through the intermediary of pins9, l0 extending from ears ll, l2 respectively which are extensions fromthe part 2. The earsll, I2 ,slide in depressions in the sides of thepart I and their forward faces, when the part 2 is drawn up to the partI, engage wedges l3, l4 disposed at the bottoms of said depressions. Thewedges are carried on threaded rods [5, I6 and ar adjustable by means ofnuts, e. g. Ill. The wedges govern the amount by which the parts of thepress may be drawn up together and constitute means for taking up wear.I 9, 20 are bolts carried on the part I, extending through the I andplaced in the press. Presure fluid is admitted 'to the cylinder 3whereby the two parts I; 2 of the press are drawn up and. the billet isbrought to a cross-sectional area and form required for treatment in thepunching or piercing apparatus. The fluid pressure in the cylinder 3 isthen released and the partsof the press are separated by the action ofthe springs 2!, 22. In this operation the flat plate's hold the billetin correct position and the press acts on it across the corners truewith the fiat faces of the billet. The sized and shaped billet is thusreleased so that it can be conveyed to a punching or piercing apparatusto be prepared for treatment in a further apparatus such as a push benchapparatus of the kind described in the Patent No. 1,979,579 or in apilger or automatic mill or other apparatus. The plates may be removableand arranged to be stationary when the parts of the press are separatedor one or more of them may move with a part or parts of the press.Instead of plates other means may be employed to engage the faces of thebillet to maintain its axis central in the press while the pressoperates across the corners of the billet. In Fig. 3 a liner 23 is shownwhich is so shaped as to produce a slightly rounded edge at one end ofthe billet.

The press produces as accurately as possible the required size acrossthe corners of the billet. By treating the billet to bring itscross-sectional area and form to that required to fit the container ofthe punching or piercing apparatus, in accord- 'ance with the presentinvention, it is possible to 45 'use the same liner in the container ofthe punching or piercing apparatus for treating portions of a billetfrom any part oi: the same cast billet.

What Iclaim is:

l. A method of producing a metal tubular article consisting in pressinga heated billet between jaws to reduce its cross-section throughout itslength to the areaand form required to be received into the container ofa punching apparatus, introducing it after such pressing into thecontainer of said punching apparatus, forcing in a punch from one end,removing the tubular hollow thus produced from the container andtreating it in a reducing apparatus to convert it into a tubulararticle.

2. A method of producing a metal tubular article according to claim 1,wherein the billet is polygonal and is pressed across its corners whileits axis is maintained-central.

3. A press for reduclngthe cross-section of a billet in the productionof a tubular article constituted of two parts with depressions in theiradjacent faces for engaging the billet, means disposed in the saiddepressions for maintaining the axis of the billet central in the pressduring pressing. a power cylinder connected to one part and a piston insaid cylinder connected to the other part so that relative movement ofthe piston and cylinder in one direction causes the press parts to closetogether and in the other direction to open.

4. A press according to claim 3 wherein the depressions are shaped atone end to produce a rounded edge at one end of the billet.

5. A press according to claim 3 having. a removable liner in two partsarranged in the depressions and having the billet-centralizing meansarranged in the said liner.

6. A press according to claim 3 having plates in the depressions toengage flat faces of the billet for the purpose of maintaining the axisof the billet central in the press while the press operates across thecorners of the billet.

7. A method of producing a metal-tubular article, comprising the stepsof pressing a hot polygonal billet transversely of its axis to reduceits cross-section throughout its length to the area and form requiredfor it to be received into the container of a piercing apparatus,introducing the billet after such pressing into the said container,forcing the punch of the piercing apparatus into the billet from oneend, removing the tubular hollow thus produced from the container, andreducing and elongating the said hollow to the form of the tubulararticle in push-bench apparatus.

8. A method according to claim 7, wherein the billet is pressedacross-its corner edges only and without being subjected at the sametime to any axial pressure.

9. A press for reducing the cross-section of a polygonal billet fromwhich a tubular article-is to be produced, comprising two co-actingpressparts with depressions in their adjacent faces to form a cavity forreceiving the billet and engaging it across its corners, means in thedepression to engage flat faces of the billet for maintaining its axiscentral in the-press whilst pressure is exerted across the corners, apower cylinder connected to one press-part and a piston in said cylinderconnected to the other press -part.

10. A method of producing a metal tubular article, comprising the stepsof treating a hot polygonal billet to reduce its cross-sectionthroughout its length to the area and tapered form required for it to bereceived into the tapered container of a piercing apparatus, introducingthe billet after such pressing into the said container, forcing thepunch of the piercing apparatus into the billet from one end, removingthe tubular hollow thus produced from the container, and reducing andelongating the said hollow to the form of the tubular article inpush-bench apparatus.

.- SYDNEY SMITH.

